Multiple choice

In the following questions, calculate quantity I and quantity II, compare them and answer Quantity I- Speed of Train (in kmph), A train covers a certain distance of 630km at constant speed. If speed of train increased by 20 kmph. Then journey would take 2 hours less. Quantity II-Average speed (in kmph), A train covers half journey at the speed of 60 kmph and half of journey at the speed of 80 kmph.

  1. If quantity I > quantity II

  2. If quantity I < quantity II

  3. If quantity I ≥ quantity II

  4. if quantity I ≤ quantity II

  5. if quantity I = quantity II or no relation can be established
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Solving 630/v - 630/(v + 20) = 2 gives v = 70 kmph. The average for equal distances at 60 and 80 kmph is 2 x 60 x 80/(60 + 80) = 68.57 kmph, so Quantity I is greater.

AI explanation

For Quantity I, assume the original speed is x kmph, so the original time is 630 divided by x and the new time is 630 divided by the sum of x and 20. Setting the difference to 2 hours yields the quadratic equation x squared plus 20x minus 6300 equals 0, giving a positive speed of 70 kmph. For Quantity II, the average speed for equal distances is calculated as 2 multiplied by 60 multiplied by 80, divided by the sum of 60 and 80, resulting in 68.57 kmph. Comparing the two values shows that 70 is greater than 68.57, meaning Quantity I is greater than Quantity II.

Keep practicing — related questions